The present invention relates to a nanocomposite solution with multi-function and a method for preparation thereof, further particularly to, solution in which nano-sized silica or silver dispersed in a combined state in water or organic solvent such as dimethylformamide (DMF), Dimethylacetamide (DMAC), etilenglicol (EG), glycerine and a method for preparation thereof.
A representative manufacturing process of silica colloid solution used in the present invention is disclosed in the U.S. Pat. Nos. 2,892,797 and 3,252,917. According to the disclosed manufacturing process, the silica colloid solution is manufactured in a method of controlling proper concentration by extracting silica of a controlled particle size as acid is added in water glass and by passing sodium and anion in the solution through anion exchange resin and ion exchange resin, respectively.
A process of manufacturing nano particles of high purity silver is divided into a top-down method of manufacturing the high purity silver of small size in a bulk state, and a bottom-up method of manufacturing by combining tens of silver atoms or silver ions. A particle of nano size always forms an oxidized film on a surface thereof when it is exposed on air because the atmosphere of the earth is mainly full of oxygen. Accordingly, the oxidized film always exists on the surface of a nano particle of pure metal. The oxidized film becomes relatively thicker in a nano state than in the bulk state, making metal particles of nano size less effective. Also, the particles of nano size hardly exist separated from each other because an agglomeration always occurs among the particles due to a tendency that each particle minimizes its surface area. However, in dispersion media such as water, or organic solvent, the particles of nano size can exist stably according to the kind of the dispersion media, and concentration and degree of agglomeration differ according to each particle. Particularly, the water is used as the dispersion media of the nano particle because the water is most common material on the earth, most environment-friendly, and applicable to broad application fields. Hereinbelow, conventional technologies related to manufacturing of silver particle solution of nano size are described.
A method of manufacturing and an application of silver sol with a silver particle having size between 1 and 100 nm dispersed in a medium with weight percentage ranging from 1 to 80 are disclosed in Korean patent publication no. 1998-018046. According to the disclosure, a silver corpuscle is manufactured by allowing silver composition solution to react with reducing agent under a temperature ranging from 5 to 50° C. and an agitation speed ranging from 1,000 to 10,000 rpm. The manufactured silver corpuscles are collected by a centrifugal separator, and dispersed in the medium again. The silver sol can be processed to be transparent conductive coating agent by adding bonding agent as necessary and can be applied to a cathode ray tube.
A method of manufacturing composite metal particle of nano size in solution using surface active agent is disclosed in Korean patent publication no. 2000-0018196. According to this disclosure, composite metal ion solution dissolved with two kinds or more of salt composites such as gold, silver, iron, platinum, and zinc is added with one kind or more of reducing agents such as hydrazine, NaBH4, LiAlBH4, and oxo compound to be resolved into composite metal particles. In this process, the surface active agents such as hydrocarbon type, silicon type, and fluorocarbon type is added to block growing of the composite metal particles and to keep the size of the particle at nano size. Also, antioxidant such as butylhydroxy toluene, and vitamin E derivative is used to prevent oxidization of a surface of metal particles. The manufactured composite metal particles are used for the purposes of antibacterial, sterilization, medicine, abrasive material, antistatic, electromagnetic wave protection, photosensitivity.
A method of manufacturing colloid of nano size using radiation exposure is disclosed in Korean patent publication no. 2001-0078858. Specifically, in-process material is removed by adding alcohol after silver salt such as AgNO3, AgClO4, and AgClO3 is melt in water. After a nitrogen substitution by adding colloid stabilizer, silver colloid particles having constant distribution is manufactured by radiation exposure. Herein, the alcohol is chosen from a group of methanol, ethanol, isopropanol, normal propanol, and butanol, and the stabilizer is chosen from a group of sodium dodecyl sulfate, polyvinyl alcohol, and polyvinylpyrollidone. The colloid manufactured according to the method disclosed in the above invention can be used as scattering enhancer for raman spectrograph, addition agent of ink activator, antibacterial and antibiosis material, conductive adhesive, and electromagnetic wave blocker.
A method of manufacturing antibacterial soup containing silver of high density using silver colloid is disclosed in Korean patent publication no 2001-0069644. In other words, it discloses a method of manufacturing low-cost antibacterial silver soup that overcomes disadvantages of a conventional silver soup such as high cost, and limited mass production. The silver colloid used therein contains the silver having high density of over 50,000 ppm and manufactured in a state of silver salt solution using reducer and surface active agent. Accordingly, this disclosure made profitable mass production possible in manufacturing the soup.
A manufacturing apparatus of gold and silver colloid is disclosed in Korean Utility Model first publication No. 2000-0021401. In installing the manufacturing apparatus of the gold and silver colloid comprising a power supply, a timer, an electrolysis circuit line, and silver plate, parts on the silver plates with small area are installed to be opposed with a constant distance. Meanwhile, a standardized product used for containing distilled water, or purified water is employed as a container.
A manufacturing apparatus of silver solution being capable of manufacturing the silver solution efficiently in a rapid speed is disclosed in Korean Utility Model first publication No. 2001-0001169. The manufacturing apparatus comprises a body comprising an inner drum forming space where distilled water is accommodated inside, an outer drum surrounding a circumference of the inner drum and accommodating the inner drum, and a cover opening/closing an upper opening of the body; two silver electrode rods inserted into the distilled water in the body; a power supply applying an alternative voltage of 110 V or 220 V with frequency of 60 Hz to the silver electrode rods; a frequency modifier to increase the frequency; and a transformer to increase voltage. Also, this apparatus is distinctive in that it can manufacture the silver solution in a short time.
A method of manufacturing metal colloid, particularly platinum colloid is disclosed in Korean Utility Model first publication No 2001-0070070. According to this disclosure, A temperature during a reducing process can be controlled by adding metal ion solution and ph compensation agent into solution mixed with water and the surface active agent. The platinum colloid can be manufactured by reducing metal ion by controlling the temperature in a manner described above and stirring. Herein, ethanol is used as the reducer, and polysorbate 80 is used as the surface active agent, and sodium carbon hydrogen is used as the pH compensation agent. An oxidization reduction potential after completion of the reduction process is over −400 mV.
A method of electrically manufacturing colloid having particle size of 30 nm or below with one or more of a group comprising metals from group Ib, group IIb, group III, group IV, group V, group VI, group VIIb, group VIII, lanthanoid, actinoid is disclosed in U.S. Pat. No. 5,925,463. According to this disclosure, after metal electrodes are dipped in electrolytic cell added with electrolyte, a reduction process occurs on a negative electrode with currents applied. Herein, Quaternary amine composite such as Tetraoctylammonium bromide is added as stabilizer, and organic solvent such as tetrahydro furan is used as dispersion media.
A manufacturing apparatus of silver colloid and a method of manufacturing the silver colloid are disclosed in U.S. Pat. No. 6,214,299. The manufacturing apparatus comprises plurality of electrodes attached with silver wire and installed on a 15-gallon container in each direction centering a rotating stirring rod. Herein, each electrode is connected to a transformer. By filling the container with water and supplying the electrode with power, silver particles are separated from the silver wire and dissolute. In this way, the silver colloid is manufactured.
High purity silver can exist as an ion or a particle in water dispersion media with extremely low concentration. Also, it can exist in several ppm, which is a relatively high concentration, with a form of complex compound (ion composition) with another anion. The High purity silver of such state is called colloidal silver.
One method of dispersing silver nano particles stably in high concentration in water dispersion media or organic solvent dispersion media is preventing the silver from settling according to Stokes' Law by adjusting viscosity of the water dispersion media or the organic dispersion media in a state of nano particle (viscosity adjuster is added).
Also, by applying ionic media such as the surface active agent on a surface of nano silver particles, particles can be ionized with a same sign so that the nano silver particles are dispersed stably by retraction force applied by ionic character among particle of same ionic sign. Another method is combining with stable composition having ionic character in a form of complex ionization or complex compound in the water dispersion media or the organic solvent dispersion media.
However, nano silver solution having the nano silver particles dispersed in the water dispersion media or the organic solvent dispersion media dose not contains nano particles in a complete metal state, but contains ionic character partially. Accordingly, as time passes by, the ionic character or the complex ionization composition becomes unstable, causing deposition or settling in the container. Also, as the nano silver solution being unstable thermally and dispersed in the water dispersion media or the organic solvent dispersion media is heated, agents such as adjuster, stabilizer, surface active agent, complex ionization composition lose their function. Accordingly, agglomeration occurs among most of the particles, and the nano silver particles are settled. Most of the conventional silver nano colloidal products are restricted in industries due to the ionic character, instability in high temperature.